Why do I need to restart my NodeBB every couple of hours ?

I am hosted on AWS EC2 with MongoDB (DB is also hosted on the same AWS EC2) ...3 categories, 1000 topics and total 1500 posts. The NodeBB becomes unresponsive after an hou or so and I am forced to restart. Nothing in the logs !
Running NodeBB v1.0.0.
Any ideas ?